1. Technical Field
The present invention relates to a linear vibration motor.
2. Description of the Related Art
A vibration function of feeding-back reception, origination, a key input state, and the like, to a user of a cellular phone is a necessary function of the cellular phone. In order to implement the vibration function as described above, a coin type/bar type vibration motor and a linear vibration motor have been mainly used. In the past, the vibration function has been used to only feed-back simple reception. However, in a current touch type smart phone, as the vibration function is used in an application such as a messenger, a game, or the like, a long lifespan and a rapid response time have been demanded. In order to satisfy these demands, a linear vibration motor has been used in most of the current smart phones.
Basically, the linear vibration motor is an actuator desired so that a weight and a spring structure supporting the weight have a specific resonant frequency and is driven by an interaction between permanent magnets by inputting sign power close to the resonant frequency to an electromagnet having a winding coil form. The linear vibration motor should secure an internal space enough to move and accelerate the weight in order to maximize vibration force and be designed to have a slim appearance so as to satisfy a demand for slimness by a customer (a terminal manufacturer).
However, a linear vibration motor according to the prior art including the following Prior Art Document has problems such as noise and deterioration in reliability that are structurally caused and a difficulty in improving electromagnetic force.